A novel method to prepare Ti1.4V0.6Ni alloy covered with carbon and nanostructured Co3O4, and its good electrochemical hydrogen storage properties as negative electrode material for Ni-MH battery

We describe our recent progress on a novel method to prepare Ti 1.4 V 0.6 Ni hydrogen storage alloy covered with nanostructured Co 3 O 4 by utilizing zelolitic imidazolate framework 67 (ZIF-67) as the template. Ti 1.4 V 0.6 Ni@C@Co 3 O 4 composite is prepared through a dopamine self-polymerization and a facile precipitation reaction with the subsequent thermal treatment. This specific composite structure combines the high conductivity of carbon together with the promising catalytic property of nanostructured Co 3 O 4 , therefore the enhanced electrochemical activity and stability are realized. As a result, Ti 1.4 V 0.6 Ni@C@Co 3 O 4 composite electrode possesses a capacity conservation rate of 56.1% after 300 charging/discharging cycles, remarkably larger than that of Ti 1.4 V 0.6 Ni (25.3%). Moreover, a study of the kinetics demonstrates that nanostructured Co 3 O 4 coating accelerates the charge-transfer reaction of the electrode. These results prove that coating with carbon and nanostructured Co 3 O 4 is a potential method for enhancing electrochemical hydrogen storage properties of hydrogen storage alloys.